suraj.sun writes: The 260 square-kilometer (100 square miles) ice island separated from the Petermann Glacier in northern Greenland early on Thursday, researchers based at the University of Delaware said.

The ice island, which is about half the height of the Empire State Building, is the biggest piece of ice to break away from the Arctic icecap since 1962 and amounts to a quarter of the Petermann 70-kilometer floating ice shelf, according to research leader Andreas Muenchow.

Environmentalists say ice melt is being caused by global warming with Arctic temperatures in the 1990s reaching their warmest level of any decade in at least 2,000 years, according to a study published in 2009.

Current trends could see the Arctic Ocean become ice free in summer months within decades, researchers predict.